Abrasive disk



Sept. 18, 1945. F. o, ALBERTSQN 2,385,249

ABRASIVE DI SK Filed June 12, 1944 Patented Sept. 1.8, 1945 e i UNITED STATES PATENT OFFICE ARAsIvE DISK Frank Osbern Albertson, Sioux City, Iowa, as-

signor to Albertson & Company, Inc., Sioux City, Iowa, a corporation of Iowa Y Application June 12, 1944i., Serial No. 539,896

j 1 Claim. (Cl. 51-195) This invention relates to abrasive disks, and e Fig. 2 is a. front f ace view of the' abrasive disk more particularly to that type of abrasive disk with a portion thereof broken away toV reveal the that is capable of being mounted upon and driven surfacing pad or rotary head whereon the disk with a so-called surfacing pad or rotary head is operatively mounted; and characterized by a yielding circular part contact- 5 Fig. 3 is an enlarged fragmentary view, genering the back or inner face of the disk, acentrally ally similar' to Fig. 2, in which the driving lwings e located centering hub, and a plurality of locking v 1iaree-Iloeeiigdenictedrinsection tdreveel the exwings disposed adjacent to the centering hub. tenslve on center" sides of the slots which are Generally speaking, an abrasive disk intended for in driven engagement with such wings. use with a surfacing pad or rotary head so charl0 Similar characters of reference refer to simiacterized consists of a relatively stiff circular lar parts throughout the several views.

backing piece having a coating of abrasive par- The abrasive disk comprises a circular backtlcles bonded toits front or outer facej a cening piece I Il of ber, cardboard, cloth or other tral aperture for receiving the centering hub, Y suitable material having its front or outer face and slots radiating from the central aperture to vebrnpletely covered with abrasive particles I I- receive the locking wings. that preferably have been adhered to the back- Hltherto it has been the practice to distort thee-ving piece by a suitable binder in the nature of a slot sides in threading the locking wingsinto and synthetic phenolic resin. fout of the slots, and in some linstances it has The abrasive disk is intended for use, in surbeen the practice tomprovide the abrasive disk facing Operations, with a Conventional SurfaCing vwith comparatively large holes, in which the Dad or rotary head =comprising the rigid power outer ends of the slots terminate, in order to predriven central portion I2, the eXible marginal vent radial tearing resultant f-romvstrain thrown DOrtiOn I3?1 the/,"centering hub I4, Carried by the upon the slot edges from becoming soy extended as Central DOItiOnI I2, and the locking Wings I5|5 to destroy the disk, These practices ofthe prior'2 5 alSOCarred by the central portion I2. There art have been far from satisfactory evenlwhen may be but tWO 0f the IOCking Wings `l5 as Shown, the slotted centralfportion of the disk has. been in WhiChiCaSe they are diametrically oppOSite With devoid 0f any abrasive coating, andhave been reference t0 thevcenterng hllb I4.` However, if

definitely unsatisfactory in respect of disks havdesiredy 'there may be four 0f the OCkng Wings ing their front faces covered with resin bonded 3 I5 equidistantly spaced around the entering hub abrasive particles. A resin bonded abrasive ovei]- |4- The hase DOItOnS `0f the locking Wings I 5 are lying the backing piece at the slot sides renders ahChOred in any Suitable fashion tO the DOrtOn volitional distortion of the slot sides difficult and 2 SllCh locking Wings extend radially With revery undesirable because tending greatly to'min SIJCCt tothub |4- They also CXtChdOr ShOlt diS- imize the total service the disk is capable of ren- 35 tanCeS at right angles t0 that faCe 0f DDrtiOn l2 dering. *Y to which they are anchored and are then turned A salient object of my invention is to provide to extend circumferentially of and parallel withk an abrasive disk, of the centrauy apertured rathe front face of the surfacing pad with the free s dially slotted type that practicably may have its end 0f CaChiOCkng Wing trailing with reference entire front or outer face completely covered 40 t0 the dllectln 0f Pad Tomi/i011- with a resinbonded abrasive, having slots into Referring again to the abrasive disk, it is PrO- and from which' the locking wings readily may be vided with a central circular aperture I6 to rethreaded without distortion of the slot sides deceive the centering hub I4. It is also provided spite that the slots are capable of cooperating With slots l1 to receive the locking wings I 5. Each with the locking wings to prevent objectionable S1011 IT merges into the aperture I6 and is delost-motion between the abrasive disk and the ned by tWO COmDaratVely 10mg Straight sides I8 pad t and I8a joined by a curved side I9, which pref- Another object of my invention is to have the erabiy is struck from a center located Within the slots present extensive straight on center" sides 510i?. Each Straight Side I3 iS truly radial 0r for driven engagement with the locking wings. 0 0n Center With respect to the aperture |6 In the accompanying sheet of drawings illusand With reSlJeCt t0 the Centering hub I4 when traimg my invention; the' abrasive disk is properly mounted upon the Fig. 1 is a front face view, somewhat in per- Surfacing pad as depicted in Figs. 2 and 3. Conspective, of an abrasive disk embodying my pres- Sequently, the straight sides I8 an`d IBa of each ent invention; v SlOt l'l are COmDaratvely close together at the disir tothe surfacing pad, and its removal therefrom, without any distortion o1 the slot sides in so doing, while preventing objectionable circumferential lost-motion between the abrasive disk and the surfacing pad, and (b) ensuring substantial contact. in lines. "on center with the axis of disk and pad rotation, between each locking wing and the alot side in respect of which such wing is in 'driving relationship.

Having thus illustrated and described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:`

An abrasive disk adapted to be mounted on a surface pad including a centering hub anda plul rsuty or disk holding and driving wings ssen hsvy assenso f of the slot and are substantially spaced ing radially disposed disk driving portions adja cent the hub and substantiallyk perpendicular to the surface pad, and disk holding portions in spaced and substantially parallel relation to the surface pad, said abrasive disk comprising a relatively stlff circular backing sheet with a coating oi abrading particles on one face thereof. said abrasive disk also having a central aperture for receiving the centering hub of the surface pad and a plurality lof slots extending outwardly from the central aperture to receive the driving portions of said wings, each of said slots being symmetrical about a4 radial axis and having outwardly diverging, radial, straight sides terminating in an arcuate surface tangent to said sides at their outer ends so that the slots are devoid of sharp corners. said straight sides being relatively close together where the slot merges into the central aperture and being of a length practically equal to that of said driving portions oi the wings so as to have full length engagement with said driving portions.

FRANK OSBERN ALBERTSON. 

